New Four-Quadrant CMOS Current-Mode and Voltage-Mode Multipliers

In this paper, a four-quadrant current-mode multiplier based on a new squarer cell is proposed. The multiplier has a simple core, wide input current range with low power consumption, and it can easily be converted to a voltage-mode by using a balanced output transconductor (BOTA) [1]. The proposed four-quadrant current-mode and voltage-mode multipliers were confirmed by using PSPICE simulation and found to have good linearity with wide input dynamic range. For the proposed current-mode multiplier, the static power consumption is 0.671 mW, the maximum power consumption is 0.72 mW, the input current range is ± 60 μ A, the bandwidth is 31 MHz, the input referred noise current is 46 pA/√Hz, and the maximum linearity error is 3.9%. For the proposed voltage-mode multiplier, the static power consumption is 1.6 mW, the maximum power consumption is 1.85 mW, the input voltage range is ± 1V from ± 1.5V supply, the bandwidth is 25.34 MHz, the input referred noise voltage is 0.85 μV/√Hz, and the maximum linearity error is 4.1%. Mohammed A. Hashiesh was born in Elkharga, New Valley, Egypt, in 1979. He received the B.Sc. degree with honors from the Electrical Engineering Department, Cairo University, Fayoum-Campus, Egypt in 2001, and he received the M.Sc. degree in 2004 from the Electronics and Communication Engineering Department, Cairo University, Egypt. He is currently a Teacher Assistant at the Electrical Engineering Department, Cairo University, Fayoum-Campus. His research interests include analog CMOS integrated circuit design and signal processing, and digitally programmable CMOS analog building blocks. Soliman A. Mahmoud was born in Cairo, Egypt, in 1971. He received the B.Sc. degree with honors, the M.Sc. degree and the Ph.D. degree from the Electronics and Communications Department, Cairo University—Egypt in 1994, 1996 and 1999 respectively. He is currently an Assistant Professor at the Electrical Engineering Department, Cairo University, Fayoum-Campus. He has published more than 50 papers. His research and teaching interests are in circuit theory, fully integrated analog filters, high frequency transconductance amplifiers, low voltage analog CMOS circuit design, current-mode analog signal processing and mixed analog/digital programmable analog blocks. Ahmed M. Soliman was born in Cairo Egypt, on November 22, 1943. He received the B.Sc. degree with honors from Cairo University, Cairo, Egypt, in 1964, the M.S. and Ph.D. degrees from the University of Pittsburgh, Pittsburgh, PA., U.S.A., in 1967 and 1970, respectively, all in Electrical Engineering. He is currently Professor Electronics and Communications Engineering Department, Cairo University, Egypt. From September 1997–September 2003, Dr Soliman served as Professor and Chairman Electronics and Communications Engineering Department, Cairo University, Egypt. From 1985–1987, Dr. Soliman served as Professor and Chairman of the Electrical Engineering Department, United Arab Emirates University, and from 1987–1991 he was the Associate Dean of Engineering at the same University. He has held visiting academic appointments at San Francisco State University, Florida Atlantic University and the American University in Cairo. He was a visiting scholar at Bochum University, Germany (Summer 1985) and with the Technical University of Wien, Austria (Summer 1987). In 1977, Dr. Soliman was decorated with the First Class Science Medal, from the President of Egypt, for his services to the field of Engineering and Engineering Education. Dr Soliman is a member of the Editorial Board of Analog Integrated Circuits and Signal Processing. Presently Dr. Soliman is Associate Editor of the IEEE Transactions on Circuits and Systems I (Analog Circuits and Filters).     

New 1.5-V CMOS second generation current conveyor based on wide range transconductor

This paper presents a novel CMOS low-voltage and low-power positive second-generation current conveyor (CCII+). The proposed CCII+ uses two n-channel differential pairs instead of the complementary differential pairs; i.e. (n-channel and p-channel), to realize the input stage. This solution allows almost a rail-to-rail input and output operation; also it reduces the number of current mirrors needed in the input stage. The CCII+ is operating at supply voltages of ±0.75 V with a total standby current of 133 μA. The application of the proposed CCII+ to realize a MOS-C second order maximally flat low-pass filter is given. PSpice simulation results for the proposed CCII+ and its application are given. Ahmed H. Madian was born in Jeddah, Saudi Arabia in 1975. He received the B.Sc. degree with honors, and the M.Sc. degree in electronics and communications from Cairo University, Cairo, Egypt, in 1997, and 2001 respectively. He is currently a Research Assistant in the Electronics Engineering Department, Micro-Electronics Design Center, Egyptian Atomic Energy Authority, Cairo, Egypt. His research interests are in circuit theory; low-voltage analog CMOS circuit design, current-mode analog signal processing, and mixed/digital applications on filed programmable gate arrays. Soliman A. Mahmoud was born in Cairo, Egypt, in 1971. He received the BSc degree with honors in 1994, the MSc degree in 1996, and the PhD degree in 1999, all from the Electronics and Communications Department, Cairo University, Egypt. He is currently an Associate Professor at the Electrical Engineering Department, Fayoum University, Egypt. He is currently also a visiting Associate Professor at the Electrical and Electronics Engineering Department, German University in Cairo, Egypt. In 2005, He was decorated with the Science Prize in Advanced Engineering Technology from the Academy of Scientific Research and technology. His research and teaching interests are in circuit theory, fully-integrated analog filters, high-frequency transconductance amplifiers, low-voltage analog CMOS circuit design, current-mode analog signal processing, and mixed analog/digital programmable analog blocks. Ahmed M. Soliman was born in Cairo Egypt, on November 22, 1943. He received the B.Sc. degree with honors from Cairo University, Cairo, Egypt, in 1964,the M.S. and Ph.D. degrees from the University of Pittsburgh, Pittsburgh, PA., U.S.A., in 1967 and 1970, respectively, all in Electrical Engineering. He is currently Professor Electronics and Communications Engineering Department, Cairo University, Egypt. From September 1997-September 2003, Dr Soliman served as Professor and Chairman Electronics and Communications Engineering Department, Cairo University, Egypt. From 1985-1987, Dr. Soliman served as Professor and Chairman of the Electrical Engineering Department, United Arab Emirates University, and from 1987-1991 he was the Associate Dean of Engineering at the same University. He has held visiting academic appointments at San Francisco State University, Florida Atlantic University and the American University in Cairo.He was a visiting scholar at Bochum University, Germany (Summer 1985) and with the Technical University of Wien, Austria (Summer 1987). In November 2005, Dr Soliman gave a lecture at Nanyang Technological University, Singapore.Dr Soliman was also invited to visit Taiwan and gave lectures at Chung Yuan Christian University and at National Central University of Taiwan. In 1977, Dr. Soliman was decorated with the First Class Science Medal, from the President of Egypt, for his services to the field of Engineering and Engineering Education. Dr Soliman is a Member of the Editorial Board of the IEE Proceedings Circuits, Devices and Systems. Dr Soliman is a Member of the Editorial Board of Analog Integrated Circuits and Signal Processing. Dr Soliman served as Associate Editor of the IEEE Transactions on Circuits and Systems I (Analog Circuits and Filters) from December 2001 to December 2003 and is Associate Editor of the Journal of Circuits, Systems and Signal Processing from January 2004-Now.     

A MC-CDMA Mobile Communication System Employing Pre-Rake and Transmit Diversity

In this paper, a multi-carrier code division multiple access (MC-CDMA) downlink mobile communication system employing pre-rake and dual transmit diversity is proposed. It combines high spectral efficiency with an immunity to channel dispersion and fading. It also ensures small size, cost and power consumption of the terminal. Theoretical and simulation results for the system under consideration are obtained. Depicted results show appreciable improvements of the proposed system over those previously known.Emad K. Al-Hussaini received his B.Sc degree in Electrical Communication Engineering from Ain-Shams University, Cairo, Egypt, in 1964 and his M.Sc and Ph.D. degrees from Cairo University, Giza, Egypt, in 1974 and 1977, respectively. From 1964 to 1970, he was with the General Egyptian Aeroorganization. Since 1970, he has been with the Department of Electronics and Communications, Faculty of Engineering, Cairo University, and is currently professor there. He was a research fellow at Imperial College, London, UK, and at the Moore School of Electrical Engineering, University of Pennsylvania, Philadelphia, PA, USA, in the academic years 1976/1977 and 1981/1982, respectively. In 1990, he received the Egyptian national encouragement award for outstanding engineering research. He has written several papers for technical international journals and conferences. His research interests include signal processing, fading channel communication, modulation, and cellular mobile radio systems. Dr Al-Hussaini is a senior member of IEEE. He is listed in Marquis Whos Who in the World and in the IBC (International Biographical Center, Cambridge) for outstanding people of the 20th century.Hebat-Allah M.Mourad received her B.Sc, M.Sc and Ph.D degrees in Electrical Communication Engineering from Cairo University, Egypt, in 1983, 1987 and 1994 respectively. Since 1983 she has been with the Electronics and Communications Department, Faculty of Engineering Cairo University and is currently associate professor there. Her research interests include mobile communications, satellite communications and optical fiber communications.Fatma A. Newagy received her B.Sc and M.Sc degrees in electrical communication engineering from Cairo University, Egypt in 1998 and 2002 respectively. Since 1999, she has been a research assistant with the Department of Electronics and Communications, Faculty of Engineering, Cairo University. She is pursuing her Ph.D. there. Her research interests include mobile communications and modulation techniques for spread spectrum and wireless communications.     

Multi-User MIMO Mobile CDMA Uplink System Employing Turbo Coding and Joint Detection Through a Multipath Rayleigh Fading Channel

In this paper, a generalized multiple-input multiple-output (MIMO) antenna system that can be fitted to the uplink of a wireless communication system is considered for the general case of multi-user. At the transmitter, the information bits are Turbo coded, then interleaved and passed through a serial-to-parallel converter. The channel is assumed bad urban suffering from multipath Rayleigh fading resulting in inter-symbol and multiple access interferences (ISI and MAI). At the front-end of the receiver, a number of receiving antennas are used followed by a joint multi-user estimator based on the Minimum Mean Square Error Block Linear Equalizer (MMSE-BLE).Computer simulations demonstrate a significant performance improvement in both single user and multi-user cases.This paper depends in parts on that presented at the 11th European Wireless Conference, Cyprus, Nicosia, pp. 187–192, April 2005. Yasmine A. Fahmy was born in Guiza, Egypt, on June 4, 1976. She received the B.Sc., M.Sc. and Ph.D. degrees in Communication and Electronics engineering from Cairo University, Egypt on 1999, 2001 and 2005 respectively. She is presently an assistant professor at Cairo University, Egypt. Her current field of interest is wireless communication and channel estimation. Hebat-Allah M. Mourad received her B.Sc., M. Sc. and Ph.D. degrees in electrical communication engineering from Cairo University, Egypt, in 1983, 1987 and 1994 respectively. Since 1983, she has been with the Department of Electronics and Communications, Faculty of Engineering, Cairo University, and is currently associate professor there. Her research interests include optical fiber communications, mobile and satellite communications. Emad K. Al-Hussaini received his B.Sc degree in Electrical Communication Engineering from Ain-Shams University, Cairo, Egypt, in 1964 and his M.Sc and Ph.D. degrees from Cairo University, Giza, Egypt, in 1974 and 1977, respectively. From 1964 to 1970, he was with the General Egyptian Aeroorganization. Since 1970, he has been with the Department of Electronics and Communications, Faculty of Engineering, Cairo University, and is currently professor there. He was a research fellow at Imperial College, London, UK, and at the Moore School of Electrical Engineering, University of Pennsylvania, Philadelphia, PA, USA, in the academic years 1976/1977 and 1981/1982, respectively. In 1990, he received the Egyptian national encouragement award for outstanding engineering research. He has written several papers for technical international journals and conferences. His research interests include signal processing, fading channel communication, modulation, and cellular mobile radio systems. Dr Al-Hussaini is a senior member of IEEE. He is listed in Marquis Whos Who in the World and in the IBC (International Biographical Center, Cambridge) for outstanding people of the 20th century.     

A Novel CMOS Realization of the Differential Input Balanced Output Current Operational Amplifier and its Applications

In this paper a new realization of the differential input balanced output current opamp is proposed, operating with ±1.5 V supplies. Its architecture is based on the use of current inverters to sense the input currents while providing a very low input resistance, 23 Ω. The opamp provides a maximum output swing of 700 μA, with an input offset current of 3.5 nA. The differential gain achieved is 65.5 dB, and the differential structure adopted in the design provided a high CMRR, 89.5 dB, the proposed circuit is compared to other realizations with single and differential inputs. The applications of the current opamp are exploited some new applications are presented such as: MOSFET-C integrators, full non-linearity cancellation for MOS transistors, and finally a digitally tuned current-mode variable gain amplifier, which has a gain tuning range of 25 dB with a 0.05 dB step.Ahmed M. Soliman was born in Cairo Egypt, on November 22, 1943. He received the B.Sc. degree with honors from Cairo University, Cairo, Egypt, in 1964, the M.S. and Ph.D. degrees from the University of Pittsburgh, Pittsburgh, PA, U.S.A., in 1967 and 1970, respectively, all in Electrical Engineering.He is currently Professor and Chairman Electronics and Communications Engineering Department, Cairo University, Egypt. From 1985–1987, Dr. Soliman served as Professor and Chairman of the Electrical Engineering Department, United Arab Emirates University, and from 1987–1991 he was the Associate Dean of Engineering at the same University. He has held visiting academic appointments at San Francisco State University, Florida Atlantic University and the American University in Cairo.He was a visiting scholar at Bochum University, Germany (Summer, 1985) and with the Technical University of Wien, Austria (Summer, 1987).In 1977, Dr. Soliman was decorated with the First Class Science Medal, from the President of Egypt, for his services to the field of Engineering and Engineering Education. Dr. Soliman is a member of the Editorial Board of Analog Integrated Circuits and Signal Processing. Presently Dr. Soliman is Associate Editor of the IEEE Transactions on Circuits and Systems I (Analog Circuits and Filters).     

A digital calibration algorithm for implementing accurate on-chip resistors

A digital calibration algorithm that provides a systematic method for implementing accurate integrated resistors without compromising linearity or noise performance is described. The technique uses a single external resistor as a reference to implement multiple, different valued integrated resistors without requiring any accurate reference voltage. The algorithm provides a method to calibrate several on-chip resistors without replicating the calibration circuit, and it can achieve an arbitrary accuracy limited only by the external resistor’s accuracy and mismatch errors. Terminations for two high speed wire line transceivers are implemented using the algorithm and simulations and measurements results show adequate performance across process, temperature, and supply voltage. Ayman A. Fayed was born Egypt, in 1975. He received the B.Sc. degree from the Electronics and Communications Department, Cairo University, Cairo, Egypt in 1998, and the M.Sc. and Ph.D. degrees from The Ohio State University, Columbus, in 2000 and 2004 respectively. Since 2002, he has been with Texas Instruments Inc. as an analog and mixed-signal circuit designer. He has been a key contributor to TI#x2019;s high-speed wire line transceivers product line. He has been awarded two US patents in the field. His research interests include mixed-signal CMOS circuit design for high-speed wire line transceivers, adaptive equalization, and power management systems. Mohammed Ismail has over 20 years experience of R&D in the fields of analog, RF and mixed signal integrated circuits. He has held several positions in both industry and academia and has served as a corporate consultant to nearly 30 companies in the US, Europe and the Far East. His current interest lies in research involving digitally programmable/configurable fully integrated radios with focus on low voltage/low power first-pass solutions for 3G and 4G wireless handhelds. He publishes intensively in this area and has been awarded 11 patents. He has co-edited and coauthored several books including a text on Analog VLSI Signal and Information Processing, (McGraw Hill). His last book (2004) is entitled CMOS PLLs and VCOs for 4G wireless, Springer. He co-founded ANACAD Egypt (now part of Mentor Graphics, Inc.) and Spirea AB, Stockholm (now Firstpass Semiconductors AB), a developer of CMOS radio and mixed signal IPs for handheld wireless applications. Dr. Ismail has been the recipient of several awards including the US National Science Foundation Presidential Young Investigator Award, the US Semiconductor Research Corp Inventor Recognition Awards in 1992 and 1993, and a Fulbright/Nokia fellowship Award in 1995. He is the founder of the International Journal of Analog Integrated Circuits and Signal Processing, Springer and serves as the Journal’s Editor-In-Chief. He has served as Associate Editor for many IEEE Transactions, was on the Board of Governors of the IEEE Circuits and Systems Society and is the Founding Editor of “The Chip” a Column in The IEEE Circuits and Devices Magazine. He is a Fellow of IEEE. He obtained his BS and MS degrees in Electronics and Communications from Cairo University, Egypt and the PhD degree in Electrical Engineering from the University of Manitoba, Canada.     

A Reconfigurable Gaussian/Triangular Basis Functions Computation Circuit

A CMOS Gaussian/Triangular Basis functions computation circuit suitable for analog neural networks is proposed. The circuit can be configured to realize any of the two functions. The circuit can approximate these functions with relative root-mean-square error less than 1%. It is shown that the center, width, and peak amplitude of the dc transfer characteristic can be independently controlled. SPICE simulation results using 0.18 μ m CMOS process model parameters of TSMC18 technology are included. Muhammad Taher Abuelma'Atti was born in Cairo, Egypt, in 1942. He received the B.Sc. degree in Electrical Engineering in 1963 from the University of Cairo, Cairo, Egypt, the Ph.D. degree in 1979 and the Doctor of Science degree in 1999 both from the University of Bradford, Bradford, England. From 1963 to 1967, he worked at the Military Technical College in Cairo as a Teaching Assistant. He was with the Iron and Steel Company in Helwan, Cairo, from 1967 to 1973 as a Senior Electrical Engineer. From 1973 to 1976 he was with the College of Engineering, University of Riyadh, Saudi Arabia, as a Teaching Assistant. From 1980 to 1981, he worked with the Faculty of Engineering, University of Khartoum, Sudan, as an Assistant Professor, and from 1981 to 1982 he was with the College of Engineering, King Saud University, Riyadh, Saudi Arabia, as an Assistant Professor. In 1982 he joined the College of Engineering, University of Bahrain and in 1987 he became an Associate Professor. In 1991 he joined the College of Engineering Sciences, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia, where he became a Full Professor in January 1995. Dr. Abuelma'Atti is the recipient of the 1994/1995 Excellence in Teaching Award and the 1995/1996 and 2000/2001 Excellence in Research Award. Both at King Fahd University of Petroleum and Minerals. Dr. Abuelma'Atti is a contributor to Encyclopedia of RF and Microwave Engineering, Kai Chang, Editor, (New York: John Wiley, 2005), Survey of Instrumentation and Measurement, S.A. Dyer, Editor, (New York: John Wiley, 2001), The Encyclopedia of Electrical and Electronic Engineering, J.G. Webster, Editor, (New York:John Wiley, 1999), and Selected Papers on Analog Fiber-Optic Links, E.I. Ackerman, C.H. Cox III and N.A. Riza, Editors, SPIE Milestone Series, (Washington: SPIE Optical Engineering Press, 1998). His research interests include problems related to analysis and design of nonlinear electronic circuits and systems, analog integrated circuits and active networks design. He is the author or co-author of over 500 journal articles and technical presentations. Abdullah Bakri Shwehneh was born in Aleppo Syria, in 1973. He received the B. Sc. degree in electrical engineering in 1998 from Sumy State University, Sumy, Ukraine. In 2001, he received the Postgraduate Diploma in Automatic Control from Aleppo State University, Aleppo, Syria. In 2001, he joined the “Electronic Brain Company for Computer and Electronics” as an Electronic & Computer Engineer and since 2002, he is with King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia, as a Research Assistant. In June 2005 he obtained his Master of Science Degree in Analog Electronics from KFUPM. At present he is a Ph.D. student at KFUPM. His main interests are in Nonlinear circuits, VLSI Analog Design and Neural Networks hardware implementation.     

CCII-Based Grounded to Floating Immittance Converter and a Floating Inductance Simulator

A new circuit employing second-generation current conveyors (CCIIs), and unmatched resistors for converting a grounded immittance to the corresponding floating immittance with either positive or negative adjustable multiplier, is presented. Moreover, the proposed circuit can also realize a synthetic floating inductance employing a grounded capacitor depending on the passive element selection. Simulation results using 0.35 μ m TSMC CMOS technology parameters are given. Erkan Yuce was born in 1969 in Nigde, Turkey. He received the B.Sc. from Middle East Technical University and M.Sc. degrees from Pamukkale University in 1994 and 1998 respectively. He is a Ph.D. student at Bogazici University all in Electrical and Electronics Engineering. He is currently Research Assistant at the Electrical and Electronics Engineering Department of Bogazici University. His current research interests include analog circuits, active filters, synthetic inductors, and current-mode circuits. He is the author or co-author of about 10 papers published in scientific journals or conference proceedings. Oguzhan Cicekoglu was born in 1963 in Istanbul, Turkey. He received the B.Sc. and M.Sc. degrees from Bogazici University and the Ph.D. degree from Istanbul Technical University all in Electrical and Electronics Engineering in 1985, 1988 and 1996 respectively. He served as lecturer at the School of Advanced Vocational Studies Electronics Prog. of Bogazici University where he held various administrative positions between 1993 and 1999, and as part time lecturer at various institutions. He was with Biomedical Engineering Institute between 1999 and 2001. He is currently Associate Professor at the Electrical and Electronics Engineering Department of Bogazici University. His current research interests include analog circuits, active filters, analog signal processing applications and current-mode circuits. He is the author or co-author of about 150 papers published in scientific journals or conference proceedings. Oguzhan Cicekoglu is a member of the IEEE. Shahram Minaei received his B.Sc. degree in Electrical and Electronics Engineering from Iran University of Science and Technology in 1993. He received his M.Sc. and Ph.D. degrees in Electronics and Communication Engineering from Istanbul Technical University in 1997 and 2001, respectively. He is currently an Associate Professor at the Electronics and Communication Engineering Department of Dogus University in Istanbul, Turkey. He has more than 50 journal or conference papers in scientific review. He served as reviewer for a number of international journals and conferences. His current field of research concerns current-mode circuits and analog signal processing. Shahram Minaei is a member of the IEEE.     

On the Throughput Capacity of Hybrid Wireless Networks Using an <Emphasis Type="Italic">L</Emphasis>-Maximum-Hop Routing Strategy

A novel pulse shape is suggested to decrease the Inter-Carrier Interference (ICI) in an Orthogonal Frequency Multiplexing System (OFDM) due to frequency offset. Furthermore several Nyquist- I pulses recently found are also used for the same purpose. Simulation results are compared for the average ICI and for the signal to interference ratio (SIR) for the pulses under consideration. The sensitivity of the ICI to the used pulse shape and the effectiveness of the proposed pulse shape are reported. Hebat-Allah M. Mourad received her B.Sc., M. Sc. and Ph.D. degrees in electrical communication engineering from Cairo University, Egypt, in 1983, 1987 and 1994 respectively. Since 1983, she has been with the Department of Electronics and Communications, Faculty of Engineering, Cairo University, and is currently associate professor there. Her research interests include optical fiber communications, mobile and satellite communications.     

Location Management in PCS Networks by Caching Two-Level Forwarding-Pointers

One of the challenging tasks in Personal Communication Services (PCS) is to efficiently maintain the location of PCS subscribers who move from one region to another (hereafter called mobile users). When a mobile user receives a call, the network has to quickly determine its current location. The existing location management scheme suffers from high signaling traffic in locating the mobile users. Two-level forwarding pointer scheme has been proposed from per-user forwarding pointer scheme to reduce the cost of signaling traffic. In this paper, we enhance the two-level forwarding pointer scheme. When a mobile user moves from its current Registered Area (RA), which is served by Mobile Switching Center (MSC), to another RA the local switch that acts as a parent of those two MSCs maintains this movement in its memory (hereafter called cache entry). A cache entry is used to locate rapidly the mobile user instead of querying the Home Location Register (HLR) and waiting for its reply. HLR is centralized in the network and far away from the mobile users so that the signaling traffic crossing it is expensive. Sometimes the cache entry may be failed to reach the mobile user then a two-level forwarding pointers will be created from the corresponding Visitor Location Register (VLR), attached to its MSC, through a correct path to locate the mobile user. Thus, there is a saving in cost of querying the underlying HLR. The analytical results indicate that such proposal efficiently reduces the signaling traffic cost for all values of Call to Mobility Ratio (CMR), this is especially considerable when CMR ≥1, without any increase in the call setup delay. Salah M. Ramadan (samohra@yahoo.com) received the BS and MS degrees from Computers Engineering Department, Al-Azhar University, Cairo, Egypt, in 1995 and 2002, respectively. From 2002, he was a Ph.D. student in Computers Engineering Department at Al-Azhar University and is currently pursuing the Ph.D. degree, where he is a research assistant in the Wireless Networks Branch. His research interests include traffic management in ATM networks, routing protocols, mobility management in PCS networks, and mobile computing. He is currently an instructor in Cisco Academy, Egypt. Ahmed M. El-Sherbini (Sherbini@mcit.gov.eg) received the Ph.D. in Electrical and Communication Engineering, Case Western University, U.S.A. March 1983 and M.Sc. in Communication Engineering, Cairo University, Giza, Egypt, June 1980. (M. Sc. Research Studies at the Ecole Nationale Superieure des Telecommunications (ENST), Paris, France). He is the Director, National Telecommunication Institute – Ministry of Communications and Information Technology, Egypt and Professor of Electrical and Communication Engineering Dept. Faculty of Engineering, Cairo University, Egypt. M. I. Marie received his B.Sc., M.Sc. and Ph.D. in electronic and communication engineering from Cairo University on 1972, 1981, 1985, respectively. Now he is a professor of communications at Computer and System Engineering department Al-Azhar University, Cairo, Egypt. His fields of interest includes digital communication, computer networks and protocols development. M. Zaki (azhar@mailer.scu.eun.eg) is the professor of software engineering, Computer and System Engineering Department, Faculty of Engineering, Al-Azhar University at Cairo. He received his B.Sc. and M.Sc. degrees in electrical engineering from Cairo University in 1968 and 1973 respectively. He received his Ph.D. degrees in computer engineering from Warsaw Technical University, Poland in 1977. His fields of interest include artificial intelligence, soft computing, and distributed system.     

New op-amp-RC to G m -C transformation method

A new transformation method is proposed and used to transform op-amp-RC circuits to G _m -C ones with only grounded capacitors. The proposed method enables the generation of high-performance G _m -C filters that benefit from the advantages of good and well-known op-amp-RC structures and at the same time feature electronic tunability, high frequency capability and monolithic integration ability. An attractive feature of the proposed method is that it results in G _m -C structures with only grounded capacitors in spite of the presence of floating capacitors in the original op-amp-RC circuits. Ahmed M. Soliman was born in Cairo Egypt, on November 22, 1943. He received the B.Sc. degree with honors from Cairo University, Cairo, Egypt, in 1964, the M.S. and Ph.D. degrees from the University of Pittsburgh, Pittsburgh, PA, U.S.A., in 1967 and 1970, respectively, all in Electrical Engineering. He is currently Professor Electronics and Communications Engineering Department, Cairo University, Egypt. From September 1997–September 2003, Dr. Soliman served as Professor and Chairman Electronics and Communications Engineering Department, Cairo University, Egypt. From 1985–1987, Dr. Soliman served as Professor and Chairman of the Electrical Engineering Department, United Arab Emirates University, and from 1987–1991 he was the Associate Dean of Engineering at the same University. He has held visiting academic appointments at San Francisco State University, Florida Atlantic University and the American University in Cairo. He was a visiting scholar at Bochum University, Germany (Summer 1985) and with the Technical University of Wien, Austria (Summer 1987). In November 2005, Dr. Soliman gave a lecture at Nanyang Technological University, Singapore. Dr. Soliman was also invited to visit Taiwan and gave lectures at Chung Yuan Christian University and at National Central University of Taiwan. In 1977, Dr. Soliman was decorated with the First Class Science Medal, from the President of Egypt, for his services to the field of Engineering and Engineering Education. Dr. Soliman is a Member of the Editorial Board of the IEE Proceedings Circuits, Devices and Systems. Dr. Soliman is a Member of the Editorial Board of Analog Integrated Circuits and Signal Processing. Dr. Soliman served as Associate Editor of the IEEE Transactions on Circuits and Systems I (Analog Circuits and Filters) from December 2001 to December 2003 and is Associate Editor of the Journal of Circuits, Systems and Signal Processing from January 2004–Now.     

Two Proposed Blind Equalizers Using Different Constellation Matched Error Functions for QAM Signals

Although Constant Modulus Algorithm (CMA) is effective to equalize non-minimum phase channels blindly, it suffers from residual intersymbol interference (ISI) and large Mean Square Error (MSE) when applied to higher order constellations (QAM). Methods based on cost function matched to the signal constellation namely alphabet matched algorithm (AMA) were previously reported and proves its superiority on CMA concerning the MSE. Thus dual mode algorithms between CMA and AMA were introduced. A hybrid technique combining CMA and AMA using a cosine square function as a constellation matched error (CME) was lately reported. In this paper two different CME functions are introduced. The MSE of the proposed algorithms are calculated using Matlab simulation under multipath slow fading channels for different signal to noise ratios (SNR) and different levels of QAM constellations. A comparison is established among them. Depicted results show the effectiveness of the two proposed CME functions. Hebat-Allah M. Mourad received her B.Sc., M.Sc. and Ph.D. degrees in electrical communication engineering from Cairo University, Egypt, in 1983, 1987 and 1994 respectively. Since 1983, she has been with the Department of Electronics and Communications, Faculty of Engineering, Cairo University, and is currently associate professor there. Her research interests include optical fiber communications, mobile and satellite communications.     

Compact MOS Implementation of a Reaction-Diffusion CNN

A biologically inspired single layer cellular neural network (CNN) with trigger wave formation capability is presented. A novel compact MOS cell circuit is proposed which exhibits a third order I-V characteristic with negative differential resistance (NDR). Certain D.C. characteristics of both the proposed cell and the network are described and corresponding theoretical estimations are presented. It is shown that the CNN formed by resistive coupling of these cells has very low complexity and realizes a reaction-diffusion system. The dynamical network behavior is demonstrated by transient simulations of a 2D cell array at the circuit level.Koray Karahalilolu received the B.Sc., M.Sc., and Ph.D. degrees in electrical engineering from Boaziçi University, Istanbul, Turkey, in 1993, 1996, and 2002, respectively.Currently he is a Research Assistant Professor with the Department of Electrical Engineering, University of Nebraska, Lincoln. He also worked as a teaching assistant with the Department of Electrical and Electronics Engineering at Boaziçi University.His research interests include VLSI neural networks, device modeling and simulation, analog circuits and systems, and nanodevice system applications.Sina Balkr received the B.S. degree in electrical engineering from Boaziçi University, Istanbul, Turkey, in 1987, and the M.S. and Ph.D. degrees in electrical engineering from Northwestern University, Evanston, IL, in 1989 and 1992, respectively.Between August 1992 and August 1998, he was with the Department of Electrical and Electronics Engineering, Boaziçi University, as an Assistant and Associate Professor. Currently, he is with the Department of Electrical Engineering, University of Nebraska-Lincoln. His research interests include CAD of VLSI systems, analog VLSI design automation, and focal-plane computation arrays for image processing.     

A Low Voltage Wide-Input-Range Bulk-Input CMOS OTA

The G_m-C technique is extensively used for continuous-time filtering applications because it results in tunable, wideband and compact designs. In this paper, an OTA architecture using a novel bulk-input differential pair without the use of a tail current source is proposed. Good CMRR is still achieved by using the gate terminal to control the total current in the differential pair, via the use of a dummy pair. The OTA also exhibits a wide differential input range and good G_m-tunability. For this design, two standard double-poly double-metal CMOS processes were investigated: a 0.8 m process having a nominal threshold voltage of around 0.7 V and a 0.35 m process having a nominal threshold voltage of 0.5 V. Simulation results are presented for both designs while test results are presented, for the OTA, implemented using the 0.8 m process, used in a second order cochlea low-pass filter.Ivan Grech received his B.Eng.(Hons.) degree in 1993 and M.Sc. in 1996 from the University of Malta. In 1994 he joined the Department of Microelectronics at the University of Malta where he is employed as a lecturer. He received the Ph.D. degree from the University of Surrey, U.K. in 2002. His research interest is in CMOS analog integrated circuit design.Joseph Micallef received his B.Sc. Eng(Hons.) degree in electronics engineering from the University of Malta in 1972, and M.Sc. and Ph.D. degrees in electrical engineering from the University of Surrey, U.K., in 1989 and 1993, respectively. From 1973 to 1981, he was with General Instruments, engaged in work on high voltage components and circuits and on IFTs. He moved to SGS-THOMSON Microelectronics in 1981 where he was involved with packaging of MOS ICs. In 1989, he joined the Faculty of Engineering at the University of Malta and is now lecturer in the Department of Microelectronics. His current research activities include analog integrated circuit design, as well as optical properties of III-V quantum well structures.George Azzopardi photo/biography not available upon publication.Carl J. Debono photo/biography not available upon publication.     

Diversity Reception of an Asynchronous Blind Adaptive Multiuser Detector Through Correlated Nakagami Fading Channel

In this paper, blind adaptive multiuser detection (MUD) technique is developed for uplink transmission in multiuser space diversity DS-CDMA system to overcome multipath fading effect and multiple access interference. The system consists of a space diversity, a precombining blind adaptive detector (PBAD), and a weight adaptation technique based on the minimization of the mean output energy (MOE). The bit error rate (BER) performance of this receiver for asynchronous DS-CDMA signals with independent and correlated antenna branches under Nakagami fading channel for BPSK system is evaluated. It has been seen that the use of antenna diversity can yield substantial improvement in performance even if the correlation between the antenna elements is relatively large (up to 0.795). However, the large correlation values pose a significant reduction in the diversity gain in comparison with the zero correlation situation. It has also been confirmed by simulations that the PBAD provides a significant receiver performance in comparison with the RAKE receiver employing antenna diversity. Khodr A. Saaifan Born in lebanon 1978, received B.S.c. degree in electrical and electronics engineering (with honors) from Benha higher institute of technology, Benha, Egypt, in 2001, and the M.S.c. degree in communications from Cairo University, Giza, Egypt, in 2005. He is currently pursuing for the Ph.D. degree at the Cairo University. His current research interest includes space–time-coded transmission, multiple-input multiple-output (MIMO) systems, fading channels, equalization, turbo (iterative) processing, and wideband code division multiple access (WCDMA). Emad K. Al-Hussaini received his B.Sc degree in Electrical Communication Engineering from Ain-Shams University, Cairo, Egypt, in 1964 and his M.Sc and Ph.D. degrees from Cairo University, Giza, Egypt, in 1974 and 1977, respectively. From 1964 to 1970, he was with the General Egyptian Aeroorganization. Since 1970, he has been with the Department of Electronics and Communications, Faculty of Engineering, Cairo University, and is currently professor there. He was a research fellow at Imperial College, London, UK, and at the Moore School of Electrical Engineering, University of Pennsylvania, Philadelphia, PA, USA, in the academic years 1976/1977 and 1981/1982, respectively. In 1990, he received the Egyptian national encouragement award for outstanding engineering research. He has written several papers for technical international journals and conferences. His research interests include signal processing, fading channel communication, modulation, and cellular mobile radio systems. Dr Al-Hussaini is a senior member of IEEE. He is listed in Marquis Who's Who in the World and in the IBC (International Biographical Center, Cambridge) for outstanding people of the 20th century.     

Carrier Frequency Recovery Technique in OFDM Systems

Orthogonal frequency division multiplexing (OFDM) systems are highly sensitive to carrier frequency errors. In this paper, a new method utilizing pilots to do frequency synchronization in frequency domain is proposed with large estimation range. It needs no such prerequisite assumption that a perfect symbol timing synchronization [IEEE Transactions on Communications 42 (1994) 2908; 45 (1997) 1613] has been done before performing integer carrier frequency synchronization. Also, a new adjusting model for fine carrier frequency is proposed. Simulation and performance analysis show that our overall frequency estimator has high accuracy. The corresponding FPGA circuit through test in high definition TV (HDTV) prototype in Team of Expert Engineering Group (TEEG) in China proves its availability and feasibility.Bo Ai (M2001) was born in Shannxi Province in China on February 7, 1974. He received a B.Sc. degree from Engineering Institute of Armed Police Force and a Master degree, a Ph.D degree from Xidian University in 1997, 2002 and 2004 in China respectively. He has once participated in the key research project on HDTV in TEEG (Team of Engineering Expert Group) of China, and has published over forty papers in his research area till now. He is senior member of Chinese Electronics Institute (CIE), an editorial commitee member of journal of Computer Simulations. His current interests are the research and applications of OFDM technique with emphasis on synchronization.Jian-hua Ge was born in September, 1961 in JiangSu Province in China. He received the B.Sc., Master and Ph.D. degree from Xidian University in 1982, 1985 and 1989 respectively. He is now the professor in both Xidian University in Xian and Shanghai Jiaotong University in Shanghai. He is the senior member of Chinese Electronics Institute. He has won lots of scientific and technical prizes in China and published many papers. His interests are transmission communications and web security.Yong Wang (M2003) was born in Shannxi Province in China in 1976. He received a B.Sc. and Master degree from Xidian University in China in 1997 and 2002 respectively, and is now working towards the Ph.D. degree on communications in the Key Laboratory of ISN in Xidian University. He has once participated in the key research project on HDTV in TEEG of China and his interests are broadband multimedia communications.Dian-fu Zhang was born in Shannxi Province in China in 1954. He received a B.Sc. degree from Xidian University in China in 1977. He is now working as a professor and the chairman of the telecommunication department in Engineering College of Armed Police Force. His interests are mobile communications.Jun Liu was born in Beijing in China in 1963. He received his B.Sc. degree from Nanjing University Of Aeronautics and Astronautics in China in 1984. He is now a professor in Engineering College Of Armed Police Force. His research interests include integrated circuit design and artificial intelligence.     

The Effects of Non-Idealities and Current Limitations on the Simulated Inductances Employing Current Conveyors

Active devices such as current conveyors play an essential role on the performance of simulated inductances. The effects of second-generation current conveyor (CCII) non-idealities on the proposed and on the previously published inductances are investigated, in which lossless inductances are realized. CCIIs like all active devices have terminal current limitations that can not be exceeded. Thus, the values of the applied input current sources for the proposed and previously published inductances depending on the passive elements values and applied signal frequency impose restrictions on the input current of the inductor. Erkan Yuce was born in 1969 in Nigde, Turkey. He received the B.Sc. degree from Middle East Technical University and M.Sc. degree from Pamukkale University in 1994 and 1998 respectively, all in Electrical and Electronics Engineering. He is currently Research Assistant and a Ph.D. student at the Electrical and Electronics Engineering Department of Bogazici University. His current research interests include analog circuits, active filters, synthetic inductors, voltage-mode current-mode circuits. He is the author or co-author of about 4 papers published in scientific journals or conference proceedings Oguzhan Cicekogluwas born in 1963 in Istanbul, Turkey. He received the B.Sc. and M.Sc. degrees from Bogazici University and the Ph.D. degree from Istanbul Technical University all in Electrical and Electronics Engineering in 1985, 1988 and 1996 respectively. He served as lecturer at the School of Advanced Vocational Studies Electronics Prog. of Bogazici University where he held various administrative positions between 1993 and 1999, and as part time lecturer at various institutions. He was with Biomedical Engineering Institute between 1999 and 2001. He is currently Associate Professor at the Electrical and Electronics Engineering Department of Bogazici University. His current research interests include analog circuits, active filters, analog signal processing applications and current-mode circuits. He is the author or co-author of about 150 papers published in scientific journals or conference proceedings. Oguzhan Cicekoglu is a member of the IEEE.     

A Low Voltage 14-Bit Self-Calibrated CMOS DAC with Enhanced Dynamic Linearity

A 1-V CMOS current steering digital to analog converter with enhanced static and dynamic linearity is presented. The 14-bit static linearity is achieved by a background analog self calibration technique which is suitable for low voltage applications and does not require error measurement and correction circuits. To improve dynamic linearity at high frequencies, a track/attenuate output stage is used at the DAC output. Integral and differential nonlinearities of the proposed DAC corresponding to 14-bit specification are less than 0.35 and 0.25 LSB, respectively. The DAC is functional up to 400MS/s with SFDR better than 71 dB in the Nyquist band. The circuit has been designed and simulated in a standard 0.18 u CMOS technology. Saeed Saeedi was born in Tehran, Iran, in 1979. He received the B.Sc. and M.Sc. degrees in electrical engineering from Sharif University of Technology, Tehran, Iran in 2001 and 2003, respectively. Since 2002, he has been working with Iran Microelectronics Research Center, IMRC. He is currently working toward the Ph.D. degree. His research interests include analog and digital integrated circuits for communication systems and high performance data converters. Saeid Mehrmanesh was born in Arak, Iran in 1976. He received the B.Sc. and M.Sc. degrees in electrical engineering from Sharif University of Technology, Tehran, Iran, in 1999 and 2002. From 2000, he has been working with Iran Microelectronics Research Center as an analog and mixed-mode and RF-IC design engineer. Since 2004, he has been a Ph.D. student at the University of Tehran. His research interests include analog to digital and digital to analog data converters, low voltage and low power CMOS circuits, telecommunication circuits, high speed serial links and RF circuits. Mojtaba Atarodi received the B.S.E.E. from Amir Kabir University of Technology (Tehran Polytechnic) in 1985, and M.Sc. degree in electrical engineering from the University of California, Irvine, in 1987. He received the Ph.D. degree from the University of Southern California (USC) on the subject of analog IC design in 1993.From 1993 to 1996 he worked with Linear Technology Corporation as a senior analog design engineer. Since then, he has been consulting with different IC companies. He is currently a visiting professor at Sharif University of Technology. He has published more than 30 technical papers in the area of analog and mixed-signal integrated circuit design as well as analog CAD tools.This revised version was published online in May 2005 with corrections to the authors affiliations.     

Single DDCC Biquads with High Input Impedance and Minimum Number of Passive Elements

Two new configurations for the design of biquad filters with high input impedance are presented. The first configuration can synthesize low-pass and high-pass filter functions according to the passive components used. The second one can synthesize a band-pass filter function. The proposed configurations employ only one differential difference current conveyor (DDCC) as active elements and minimum number of passive elements, namely two resistors and two capacitors. Another filter topology based on DDCC is presented that allows modifying the quality factor without changing its natural frequency. All the filters enjoy low sensitivities. SPICE simulation results are given to confirm the validity of the analysis and to point out the high performance of the filters.Muhammed A. Ibrahim was born in Erbil, Iraq in 1969. He obtained his B.Sc. and M.Sc. degrees from Salahaddin University, Erbil, Iraq and Istanbul Technical University, Istanbul, Turkey in 1990 and 1999, respectively, all in electronics and communication engineering. Between 1992 and 1996 he worked as Research Assistant at Salahaddin University where he was later appointed as Assistant Lecturer in 1999. Since 2000 he has been studying for his Ph.D. degree in Electronics and Communication Engineering Program at Istanbul Technical University. His main research interests are CMOS circuit design, current-mode circuits and analog signal processing applications. He has more than 20 international journal and conference papers in scientific review.H. Hakan Kuntman received his B.Sc., M.Sc. and Ph.D. degrees from Istanbul Technical University in 1974, 1977 and 1982, respectively. In 1974 he joined the Electronics and Communication Engineering Department of Istanbul Technical University. Since 1993 he is a professor of electronics in the same department. His research interest include design of electronic circuits, modeling of electron devices and electronic systems, active filters, design of analog IC topologies. Dr. Kuntman has authored many publications on modelling and simulation of electron devices and electronic circuits for computer-aided design, analog VLSI design and active circuit design. He is the author or the coauthor of 76 journal papers published or accepted for publishing in international journals, 91 conference papers presented or accepted for presentation in international conferences, 99 turkish conference papers presented in national conferences and 10 books related to the above mentioned areas. Furthermore he advised and completed the work of 7 Ph.D. students and 31 M.Sc. students. Currently, he acts as the head of the Electronics and Communication Engineering Department in Istanbul Technical University. Dr. Kuntman is a member of the Chamber of Turkish Electrical Engineers (EMO).Oguzhan Cicekoglu received the B.Sc. and M.Sc. degrees from Bogazici University and the Ph.D. degree from Istanbul Technical University all in Electrical and Electronics Engineering in 1985, 1988 and 1996 respectively. He served as lecturer at the School of Advanced Vocational Studies Electronics Prog. of Bogazici University where he held various administrative positions between 1993 and 1999. He served also as part time lecturer at various institutions. He was with the Biomedical Engineering Institute of the Bogazici University between 1999 and 2001. He is currently Associate Professor at the Electrical and Electronics Engineering Department of the same University.His current research interests include analog circuits, active filters, analog signal processing applications and current-mode circuits. Oguzhan Cicekoglu is the author or co-author of 62 journal papers and about 90 international or local conference papers published or accepted for publishing in journals or conference proceedings.He served as the committee member in various scientific conferences and as reviewer in numerous journals including Analog Integrated Circuits and Signal Processing, IEEE CAS-I, IEEE CAS-II, International Journal of Electronics, Microelectronics Journal, Solid State Electronics and IEE Proceedings Pt.G.Oguzhan Cicekoglu is a member of the IEEE.     

A Fully Integrated Class 1 Bluetooth 0.25 μm CMOS PA

A fully integrated 0.25 m CMOS bluetooth class 1 power amplifier is presented. On this chip all inductors and decoupling capacitors are situated on the silicon die. Due to the high level of integration, a cheap flip chip assembly method has been used. The chip delivers 138 mW (21.4 dBm) of output power with a power added efficiency of 25.8%. When the amplifier is tuned to its optimum frequency of 2.1 GHz, the output power increases to 184 mW and the power added efficiency increases to 29.5%. To compare the performance of this realisation with other recently published PA, a figure of merit for saturated (switched) power amplifiers is introduced.Koen Mertens was born in Antwerpen, Belgium in 1971. He received the M.Sc. degree in Electrical Engineering from the Katholieke Universiteit Leuven, Belgium in 1998. The subject of his M.Sc. thesis was the design of a 2.14 GHz BICMOS oscillator. The thesis was in cooperation with IMEC. Since 1998. He has been a research assistant at the ESAT-MICAS laboratories, where he is currently working towards a Ph.D. degree in CMOS RF Power Amplifiers. His research promotor is Prof. Michiel Steyaert.Michiel Steyaert Michel S.J. Steyaert was born in Aalst, Belgium, in 1959. He received the masters degree in electrical-mechanical engineering and the Ph.D. degree in electronics from the Katholieke Universiteit Leuven (K.U. Leuven), Heverlee, Belgium in 1983 and 1987, respectively.From 1983 to 1986 he obtained an IWNOL fellowship (Belgian National Fundation for Industrial Research) which allowed him to work as a Research Assistant at the Laboratory ESAT at K.U. Leuven. In 1987 he was responsible for several industrial projects in the field of analog micropower circuits at the Laboratory ESAT as an IWONL Project Researcher. In 1988 he was a Visiting Assistant Professor at the University of California, Los Angeles. In 1989 he was appointed by the National Fund of Scientific Research (Belgium) as Research Associate, in 1992 as a Senior Research Associate and in 1996 as a Research Director at the Laboratory ESAT, K.U. Leuven. Between 1989 and 1996 he was also a part-time Associate Professor. He is now a Full Professor at the K.U. Leuven. His current research interests are in high-performance and high-frequency analog integrated circuits for telecommunication systems and analog signal processing.Prof. Steyaert received the 1990 European Solid-State Circuits Conference Best Paper Award, the 1995 and 1997 ISSCC Evening Session Award, the 1999 IEEE Circuit and Systems Society Guillemin-Cauer Award and the 1991 NFWO Alcatel-Bell-Telephone award for innovative work in integrated circuits for telecommunications.